Extensive research has established a positive association between caregiver-child behavioral synchrony and child developmental functioning. Burgeoning research examining physiological synchrony has yet to elucidate its impact for children's developing self-regulation. The objectives of this systematic review were to 1) determine whether there is evidence that caregiver-child physiological synchrony promotes positive child development, 2) examine developmental differences in physiological synchrony and its correlates, and 3) explore whether context, risk, and/or stress influence patterns of synchrony. Sixty-nine studies met the following criteria on PubMed and PsycINFO 1) peer-reviewed empirical articles in English that 2) examine autonomic, hypothalamic-pituitary-adrenocortical, and/or central nervous system activity 3) for caregivers and children 4) in response to a task and 5) directly examine the association between caregiver and child physiology. Findings varied based on developmental period and current behavioral context. Functional differences may exist across physiological systems and contexts. Synchrony may have different developmental consequences for dyads with and without certain risk factors. Few studies examine physiological synchrony across multiple systems or contexts, nor do they measure child characteristics associated with synchrony. Statistical and methodological challenges impede interpretation. Findings generally support the idea that physiological synchrony may support children's developing self-regulation. Longitudinal research is needed to examine child developmental outcomes over time.There is emerging evidence that the development of problematic aggression in childhood may be associated with specific physiological stress response patterns, with both biological overactivation and underactivation implicated. This study tested associations between sex-specific patterns of stress responses across the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis and peer nominations of aggression among 271 kindergarten children (Mean age = 5.32 years; 52% Female; 44% White). Upon entry to kindergarten, children participated in a multidomain standardized stress paradigm. Changes in pre-ejection period (PEP) and salivary cortisol were assessed. On a separate day, children provided peer ratings of physical and relational aggression in a standardized interview. As expected, there was a significant three-way interaction between PEP, cortisol reactivity, and sex, but only for physical aggression. Among boys, cortisol reactivity was positively associated with physical aggression only for those with higher SNS reactivity. Findings suggest that for boys, asymmetrical and symmetrical HPA/SNS reactivity may be associated with lower and higher risk for peer-directed physical aggression, respectively. Understanding the complex associations between multisystem physiology, child sex and peer-directed aggression in early childhood may offer insight into individual differences underlying the emergence of behavioral dysregulation in early peer contexts.Early adversity has been shown to sensitize individuals to the effects of later stress and enhance risk of psychopathology. Using a longitudinal randomized trial of foster care as an alternative to institutional care, we extend the stress sensitization hypothesis to examine whether early institutional rearing sensitizes individuals to stressful events in adolescence engendering chronic low-grade inflammation. At baseline, institutionalized children in Romania (ages 6-31 months) were randomly assigned to foster care or to remain in usual care within institutions. A group of never-institutionalized children was recruited as an in-country comparison sample. At ages 12 and 16, participants reported stressful events. At age 16, Interleukin-6 (IL-6) and C-reactive protein (CRP) were derived from blood spots. Among children assigned to care as usual, more stressful events at age 12, but not age 16, were associated with higher IL-6. In the same group, stressful events at age 16 were associated with higher CRP, though these effects attenuated after adjusting for covariates. These associations were not observed in the foster care or never-institutionalized groups. The findings suggest that heightened inflammation following stress exposure is one pathway through which early neglect could compromise physical health. In contrast, early family care might buffer against these risks.The hypothalamic-pituitary-adrenal (HPA) axis is sensitive to early life stress, with enduring consequences for biological stress vulnerability and health (Gunnar &amp; Talge, 2008). Low socioeconomic status (SES) is associated with dysregulation of the stress hormone cortisol in early childhood. However, a mechanistic understanding of this association is lacking. Multidimensional assessment of both SES and cortisol is needed to characterize the intricate relations between SES and cortisol function in early childhood. We assessed parent-reported family income, parent education, occupational prestige, neighborhood risk, food insecurity, and household chaos for 12-month-old infants (N = 90) and 3.5-year-old children (N = 91). Hair cortisol concentration (HCC) was obtained from parent and child, indexing chronic biological stress, and diurnal salivary cortisol was measured in the children. Controlling for parent HCC, parent education uniquely predicted infant and child HCC and, in addition, neighborhood risk uniquely predicted infant HCC. Household chaos predicted bedtime salivary cortisol concentration (SCC) for both infants and children, and infant daily cortisol output. Food insecurity was associated with flattened cortisol slope in 3.5-year-old children. Parental sensitivity did not mediate relations between SES and cortisol. https://www.selleckchem.com/products/Obatoclax-Mesylate.html Results highlight the utility of SES measures that index unpredictable and unsafe contexts, such as neighborhood risk, food insecurity, and household chaos.The majority of children living in foster care in the United States have a history of maltreatment and/or disrupted caregiving. Maltreatment in early childhood adversely affects development at many levels, including neurobiology and behavior. One neurobiological measure associated with maltreatment is alpha electroencephalogram (EEG) asymmetry. Prior research has found greater right frontal asymmetry among children with a history of maltreatment. However, little research has been extended developmentally downward to examine alpha asymmetry and its behavioral correlates among toddlers in foster care; this was the purpose of the present study. Differences in EEG asymmetry were examined between a sample of foster toddlers (mean age = 3.21 years, n = 38) and a community comparison, low-income sample without a history of foster care (mean age = 3.04 years, n = 16). The toddlers in the foster care group exhibited greater right alpha asymmetry, primarily driven by differences in parietal asymmetry. Neither frontal nor parietal asymmetry were clearly related to internalizing or externalizing behaviors, measured concurrently or at previous time points.